Solar PV and oil-filled rads

groovyf

Just a quick query...
I have electric underfloor heating in the living room (about 18m²) that sucks about 2.3Kw when it's heating - which is OK to a point in the fact that it heats up relatively quicker than a system with mats of a lesser wattage.
However, as the solar panels aren't generating that amount of kW - certainly not on a cold, cloudy day as today has been, I was wondering if an oil-filled radiator (for use during day) at a low setting of 400w (seen a B&Q model quite cheap) wouldn't be a bad idea?

Thoughts? Has anyone got such a thing for background heating?

tunnel

Have a word with Oscargrouch on the renewables thread. He has one which he uses with a Wattson and optiplug so it only turns on when there's enough spare juice to power it.

Ectophile

I've been known to switch on my small oil-filled radiator on cold but sunny days. It works quite well in keeping the downstairs of the house warm.

Many oil-filled radiators have different heat settings. I just use the lowest, because I don't know how much the panels will generate.

Martyn1981

I've got one (also from B&Q) use it all the time on cool days, when it can just cope with warming a room. Try to match it to generation, ideally when gen is 700W+, but TBH I don't mind if gen is lower, as it's probably better to pay for a small amount of leccy, to keep the living room just comfortable, than to use GCH and heat whole house, which will leak more heat.

But, don't do what I did and buy the cheapest. Mine only has 5 fins, and gets itself hot (regardless of actual room temp) so will run for about 20mins on 400W, then on and off in 10min intervals, so effectively only working as a 200Wh heater.

Might sound silly, but having the living room warm(ish) and kitchen etc cooler (within reason) actually feels nicer, and healthier, rather than one all over temp.

Mart.

groovyf

Thanks for that, Mart, just the kind of info I was after.
I've sourced a DeLonghi (650w, 850w, 1500w power settings), will have a play around with it and see how I get on.

zeupater

groovyf wrote: »

Thanks for that, Mart, just the kind of info I was after.
I've sourced a DeLonghi (650w, 850w, 1500w power settings), will have a play around with it and see how I get on.

Hi

We've got an oil rad too, slightly smaller at ~400/~600/~1100W and use it in conjunction with an ~800/~1600W ceramic fan heater to roughly match generation .... there's no automated control, but we use some infrared receiver plugs and switch the units on/off with a couple of buttons on the TV remote control.

The 400W setting is pretty good to capture generation most bright(ish) days without worrying too much about importing energy, but anything higher & you need to keep a close eye on the clouds. It's not a pretty solution, but it does mean that other heating sources aren't required just to 'take the chill off' when watching the gogglebox in spring & autumn ...

We were using a combination of the two heaters about 1/2hour ago (1600W+400W), but now it's a little cloudy so the oil rad is on at 400W. With it being pretty bright and the sun angle being quite low we're getting much more heat than the two heaters combined through solar gain, it's just that it can't be delivered to where it's most needed .... log burner used for 6Hrs yesterday, but that was the first fuelled heat input for the house for a week (well it has been pretty bright & mild for this time of year ) ... soon be summer !

HTH
Z

Kernel_Sanders

Martyn1981 wrote: »

Mine only has 5 fins, and gets itself hot (regardless of actual room temp) so will run for about 20mins on 400W, then on and off in 10min intervals, so effectively only working as a 200Wh heater.

Surely the problem is narrow thermostatic range rather than fin shortage!

Martyn1981

Kernel_Sanders wrote: »

Surely the problem is narrow thermostatic range rather than fin shortage!

Don't they go hand-in-hand!. A greater range, would work, but would mean hotter fins, and they are pretty hot already. More fins (and/or larger fins) means a greater surface area to transfer the heat from the element to the air, via the oil. Maybe mine is being over cautious.

I could, I suppose, use a fan to increase the air flow, increase the heat dissipation, increase the amount of time it stays on.

Plan B, buy a better radiator (more fins).

Plan C, put the two radiators on at the same time, but use timer plugs that are set 1/2 hour on, half hour off, but with opposite settings.

Plan D, get a small A/C unit, and turn that 400W of leccy into 1,200 to 1,600W of heat. If only I could find a company willing to ring me back!!!! :mad:

Mart.

Kernel_Sanders

Martyn1981 wrote: »

Plan B, buy a better radiator (more fins).

Plan C, put the two radiators on at the same time, but use timer plugs that are set 1/2 hour on, half hour off, but with opposite settings.

Plan D, get a small A/C unit, and turn that 400W of leccy into 1,200 to 1,600W of heat. If only I could find a company willing to ring me back!!!! :mad:Mart.

You've missed out the obvious one; halogen heaters are continuous heat and come with 400W options (mine is actually 2x 380W bars). If you don't like that sort of direct heat, why not aim it at something that will absorb it such as a hearth or, failing that, a pile of bricks in your living room?

Martyn1981

Kernel_Sanders wrote: »

You've missed out the obvious one; halogen heaters are continuous heat and come with 400W options (mine is actually 2x 380W bars). If you don't like that sort of direct heat, why not aim it at something that will absorb it such as a hearth or, failing that, a pile of bricks in your living room?

Not sure Wifey would go for the pile of bricks, but hadn't thought of a halogen heater. I have got 2 120W tubular heaters sitting on shelves in the back bedroom, currently used for computer/office/exercise etc.

They are both plugged into a switched multi-gang so I can have none/one/two on, and the multi-gang is plugged in via a timer switch, currently set to 8am to 5pm only, so that if I forget to switch it off, it doesn't draw power all night. I narrow/widen the time window a few times a year to match the longer/shorter autumn, winter & spring days.

I'm still surprised what 200 to 400W(ish) can do.

Mart.

Kernel_Sanders

Martyn1981 wrote: »

I have got 2 120W tubular heaters

Go that low and you're in tungsten filament territory! I still have a 150W bulb and whilst they are only around 93% efficient when used as heaters, that light will alert you if you forget to turn them off once darkness falls.